The wolf, OR-18, was born into the Snake River pack, said Rob Klavins, wolf expert with Oregon Wild. He was collared by Oregon Department of Fish and Wildlife biologists last March in a helicopter operation, then dispersed, looking for new territory and a mate. OR-18 traveled through Idaho and entered the Big Hole Valley in Montana, said Vivaca Crowser, spokeswoman for Montana Fish, Wildlife and Parks.

About May 15, Oregon wildlife officials called their peers in Montana, informing them that the wolf was in the Bitterroot, she said.

The next news came last week in another phone call from Oregon: The animal's collar was sending out a mortality signal. Using the GPS coordinates from the collar, Montana officials tracked down the body, which was found in a remote, mountainous area not far from a forest service road.

Wolves in Montana were declared recovered and delisted from the Endangered Species Act in 2011. The state allows wolf hunting between Sept. 15 and March 15, and, without a permit, landowners can kill wolves that threaten livestock, people or pets.

But the state did not receive any reports of threats or kills, making this one illegal, Crowser said. If the culprit is caught, he or she would face a misdemeanor fine from $100 to $1,000.

Montana asked that anyone with information about the incident call 800-TIP-MONT (1-800-847-6668). The state offers a $1,000 reward for tips that lead to a conviction.

Crowser said this is the first documented killing of an Oregon wolf in Montana.